200 WILD TRAITS IN TAME ANIMALS. 



individuals) is not directly dependent upon ease 

 and an abundant food - supply, or the reverse. 

 Size, after all, is only one of the many con- 

 ditions which go to make up conformity with 

 environment. If animals find it profitable, 

 whether for purposes of war or for the sake 

 of gaining sustenance, to be large, they will 

 tend to increase in bulk from generation to 

 generation. If, on the other hand, they find 

 it easier to maintain the struggle for existence 

 when they are small, each generation will lessen 

 them. Moreover (and this is more to the point 

 in the question as to why mountain animals 

 tend to degenerate when they are domesticated), 

 if the pressure of circumstances which is forcing 

 them to be large or to be small be removed, 

 they seem to revert to some ancient standard 

 of bulk which was probably maintained with- 

 out material alteration throughout an immense 

 epoch before the later circumstances which in- 

 fluenced their size came into operation. And 

 this traditional average standard may be said 

 to be (in so far as that often misused phrase 

 is allowable) the "natural size" of the animals. 

 One inference which arises from this suggested 

 explanation is that mountain animals are de- 



